As a follow up to this post, I bought a Tagg tracker to use at the farm. I set the safe zone as our house and fenced in area. If Fred strays outside of that which he tends to do when taking care of business, I use the locate feature on the app and it shows me how far over the hill he is away from us. I mostly use it when it is dark to make sure he is in the area. For the recall, he gets one loud whistle with a "Fred, Come" and he always responds because there is a treat with his name on it. The Tagg uses verizon which seems to be pretty good in our area.